Rapid determination of thyroid hormones in blood plasma from Glaucous gulls and Baikal seals by HybridSPE®-LC-MS/MS

Abstract A rapid hybrid solid phase extraction (HybridSPE®) protocol tailored to liquid chromatography–electrospray ionization tandem mass spectrometry (LC–ESI–MS/MS) analysis, was developed for the determination of four thyroid hormones, L-Thyroxine (T4), 3,3?,5-triiodo-L-thyronine (T3), 3,3?,5?-triiodo-L-thyronine (rT3) and 3,3?-diiodo-L-thyronine (T2) in blood plasma from Glaucous gulls (Larus hyperboreus) Baikal seals (Phoca sibirica). The use target analyte specific 13C internal standards allowed quantification be performed through standard solvent calibration curves alleviated need perform with matrix match curves. relative recoveries were 100.0–110.1 % T4, 99.1–102.2 T3, 100.5–108.0 rT3, 100.5–104.6 T2. effects ranged ?1.52 ?6.10 %, demonstrating minor signal suppression during analysis. method intra-day precision (method repeatability, RSD N = 5, k = 1 day) inter-day reproducibility, N = 10, k = 2 days) at 1 ng/mL concentration fortification 8.54–15.4 15.4–24.8 respectively, indicating acceptable chromatographic peak stabilities all THs even trace level concentrations. limit detection (LOD) rT3 T2 0.17, 0.16, 0.30 0.17 ng/mL, respectively. HybridSPE® simple (